In this homework, you are supposed to write a code find the longest word in an a

Question

In this homework, you are supposed to write a code find the longest word in an asciiz string. The string is a part of a Shakespeare play from http://www.william-shakespeare.info/act2-script-text-henry-vi-part1.htm.  

In this homework, a word of length n is defined as n consecutive ascii codes, where each code is either between ‘a’ and ‘z’ or ‘A’ and ‘Z’, inclusive.

I have provided the skeleton of the code at the end of this description of the homework. You will need to implement 3 functions. If your functions are correct, the code will print the longest word. Basically, the main program calls the “findmax” function, which returns the longest word.

# -----------------------------------------------

# findmax (40 points)

#

# $a0: the starting address of an asciiz string

# $a1: the starting address of an allocated memory space to which the maximum length word is to

#      be copied, ending with a 0 to make it an asciiz string

#

# Note: Must call the getword function to examine one word at a time

# -----------------------------------------------

# -----------------------------------------------

# getword (40 points)

#

# $a0: the starting address of an asciiz string, say, A, at this address, the content must be the

#      ascii code of an English letter, either upper case of lower case

# $a1: the starting address of an allocated memory space, to which the first word in string A can

#      be copied, ending with a 0 to make it an asciiz string

# $v0: the length of the word

#

# Note: Must call the isletter function

# -----------------------------------------------

# -----------------------------------------------

# isletter (20 points)

#

# $a0: a value

$ $v0: returns 1 if the value in $a0 is the ascii code of an English letter, 0 otherwise

# -----------------------------------------------

"

returnres : .space 100

       .text

       .globl main

main:

       la $a0, dialog

       la $a1, returnres

       jal findmax

       li $v0,4                     # now print the found longest word

       la $a0,returnres

       syscall

done:li $v0, 10              # Exit

       syscall

findmax:     

       jr $ra

getword:

       jr $ra

isletter:

       jr $ra

# -----------------------------------------------

# strcpy

#

# Note: copies the string starting at $a1 to an allocated memory space starting at $a0, the same

#       as the code we wrote in the class, will be useful

# -----------------------------------------------

strcpy:      

lb $t0, 0($a1)

       sb $t0, 0($a0)

       addi $a0, $a0, 1

       addi $a1, $a1, 1

       bne $t0, $0, strcpy

       jr $ra

Explanation / Answer

findmax (40 points)

#

# $a0: the starting address of an asciiz string

# $a1: the starting address of an allocated memory space to which the maximum length word is to

#      be copied, ending with a 0 to make it an asciiz string

#

# Note: Must call the getword function to examine one word at a time

# -----------------------------------------------

# -----------------------------------------------

# getword (40 points)

#

# $a0: the starting address of an asciiz string, say, A, at this address, the content must be the

#      ascii code of an English letter, either upper case of lower case

# $a1: the starting address of an allocated memory space, to which the first word in string A can

#      be copied, ending with a 0 to make it an asciiz string

# $v0: the length of the word

#

# Note: Must call the isletter function

# -----------------------------------------------

# -----------------------------------------------

# isletter (20 points)

#

# $a0: a value

$ $v0: returns 1 if the value in $a0 is the ascii code of an English letter, 0 otherwise

# -----------------------------------------------

"

returnres : .space 100

       .text

       .globl main

main:

       la $a0, dialog

       la $a1, returnres

       jal findmax

       li $v0,4                     # now print the found longest word

       la $a0,returnres

       syscall

done:li $v0, 10              # Exit

       syscall

findmax:     

       jr $ra

getword:

       jr $ra

isletter:

       jr $ra

# -----------------------------------------------

# strcpy

#

# Note: copies the string starting at $a1 to an allocated memory space starting at $a0, the same

#       as the code we wrote in the class, will be useful

# -----------------------------------------------

strcpy:      

lb $t0, 0($a1)

       sb $t0, 0($a0)

       addi $a0, $a0, 1

       addi $a1, $a1, 1

       bne $t0, $0, strcpy

       jr $ra

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